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View Full Version : laser engraving through faux finish background on white acrylic backlit signs


iSign
09-04-2011, 10:37 PM
well, I honestly never saw this done before, but when I bid the job, I thought i would just paint over vinyl mask... but as I got closer to time to do the work, all the 1" copy for 20 directional signs made my eyes go numb just thinking about cutting, weeding, applying AND removing all that copy... if there was a better way...

...well, it's going to cost me $50 each, but save me a lot of headache & I think it's a great solution!!

The required background color is a faux copper patina, or a mottled texture of various shades of turquoise green and copper... trending towards the darker ranges of this effect, for contrast purposes... and "sophisticated finishes" (or Triangle coatings) makes just the 2 part water base paint to do the job.

I've done several smaller samples, and now I've done a full size panel & installed it in the back lit environment to ensure day & night contrast and legibility. It's a hit! Client loves it, the result is vastly superior to the existing signage, and I consider it to be a success that nearly meets my own expectations!

I say "nearly" because I plan to improve on the original with at least one change, and possibly some other variations of production, based on questions I wish to ask here...

First, have a look at the results:

http://www.signs101.com/photopost/data/500/medium/backlitcopper2.jpg

Here is another with my sign installed in the clients 4-sided housing. Mine is on the left & an illegible old sign is shown to the right of mine:

http://www.signs101.com/photopost/data/500/medium/backlitcopper.jpg

NOW, THE QUESTION:

HOW SHOULD I PREP THE ACRYLIC FOR LONG TERM PAINT ADHESION?

MY COPPER BASE COAT IS A WATER BASE PAINT, BUT FOR GREATER DURABILITY THIS SAMPLE ALSO HAS A DURABLE FOREST GREEN HOUSE PAINT, SIMILAR TO PORTER PAINT, UNDER THE COPPER.

One change I've already planned to implement is spraying instead of rolling the 2 base coats. The opacity was good on the sample, even though there was a small amount of translucency. The client didn't mind because the textural quality of the background even shows up at night... but I could see some linear roller marks resulting from varying degrees of paint thickness, in a noticably inorganic pattern. (The final patina effect is done with a sea sponge, which of course helped hide the roller lines)

So, is a light scuff sanding of the acrylic, followed by a good rinse & tack cloth sufficient for good paint adhesion? These signs are costing me a lot to produce, and of course costing the client quite a bit more, so I want to make sure they have every chance of lasting a good long time.

Any suggestions?

GypsyGraphics
09-04-2011, 10:44 PM
don't have experience with that, so can't offer any advice... just wanted to say...
ooooo.... me likey! :rock-n-roll:

GAC05
09-04-2011, 11:25 PM
Looks good Doug, no idea on getting paint to hold up on acrylic outside.
Question on the production.
You are sending them out to be laser engraved after painting to expose the text?
Could you do something like that with a super light pass on your CNC table?

wayne k
guam usa

Custom_Grafx
09-04-2011, 11:59 PM
Whoever you're using for the lasering should know about rowmark or IPI range of similar materials, which are layered plastics.

To date, I am yet to have a request for one of these, but please refer to attached for a sample of what's available in a laserable material which might suit?

iSign
09-05-2011, 12:16 AM
wayne, the problem with the CNC idea is the size of the copy. I would have round inside corners from the rotating tool, which isn't a big deal on larger stuff, but shows up a little more on small copy. I've broken so many 1/16th tools, that I wouldn't trust expecting to make it through over 100 letters on each of 20 plaques, and the 18" tool just won't be small enough.
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but... I suppose I ought to try one huh?

Custom Grafx, thanks for the Rowmark samples. I spent a few years running engravers through all that stuff, but I wasn't familiar with that Verde green/gold fleck stuff. I don't think it would be as good for this job, even if it is a translucent backlit stock (which it appears not to be) because there are other areas i have to paint this faux patina, so my method at least will be very similar throughout the project, albeit much more labor intensive.

Custom_Grafx
09-05-2011, 12:45 AM
They do come in a version which is reverse engravable (I have used their reverse white/matt clear - it's a great product with paint fill). I imagine it should be quite hard wearing, and the engraving being on the sub surface would prevent any scratch or flaking problems you may face with the paint version.

I don't do acrylic painting myself (just infilling), but I do get some acrylic painted on occasion by my local panel shop, and they do use a specific type of primer for acrylic, then they spray it with auto body paint. The finish is real solid and I've tried chipping away at it with my fingernails etc but it doesn't come off - great adhesion.

iSign
09-05-2011, 02:35 AM
I've done miles of reverse engraved plaques, but didn't see the matte clear option for those textured samples, which would then need a white diffuser... but I'm pretty stoked with my custom solution anyway...

I would love to hear what paint your associate might be using, if you happen to ask him. Thanks

Custom_Grafx
09-05-2011, 02:47 AM
They look textured but are not... a printed pattern of some sort I guess... anyways... your painted version, definitely better as it's closer to the real thing.

I bump into him on my morning walk anyway at least 2 days out of 5, so next time I'll ask him what he uses for the primer.

I know that for the paint he just uses whatever he uses for cars... that's what he's told me anyway... I think it's a 2 pack thing.

iSign
09-05-2011, 04:29 AM
Thanks, I just got a big job out the door with a 2 stage urethane on it... What a PITA!
I think I'm back to acrylics for this next job...

watsons signs
09-05-2011, 09:49 AM
Matthews makes a spray on adhesion promoter for plastics that is clear called Tie-Bond
http://www.ppg.com/coatings/matthewspaint/products/Documents/MPC160_74777SP.pdf

iSign
09-05-2011, 01:52 PM
Thanks Watson.
I'm going to have to make some calls.
That looks like a good lead!

John Butto
09-05-2011, 03:47 PM
here are the specs...